Two qubits now map how energy spreads through quantum systems

Hossein Hosseinabadi of Johannes Gutenberg-Universität Mainz and colleagues have demonstrated that a two-qubit quantum sensor can map how energy spreads through complex quantum systems, separating the response and noise of the environment being probed, a capability extending beyond single-qubit sensing. The work reveals that this approach resolves the spatio-temporal spreading of correlations, visualizing the dispersion of low-energy excitations as light-cone-like profiles. Researchers further found that external driving can modify this profile, creating additional fringes outside the light-cone, and that the method distinguishes between different energy transport regimes including ballistic spreading and diffusive broadening. A two-qubit sensor can distinguish between ballistic, diffusive and crossover transport regimes within a quantum system, offering a new level of granularity in observing energy movement. The method relies on a T₂ spectroscopy framework, allowing this approach to resolve the spatio-temporal…